Wednesday, November 29, 2006

I wanted to use the interpolate effect to mimic motion, or at least generate a smooth flow between static images. I thought I might be able to use this effect for video overlays and such.

For the experiment, I used four png images, each with a green dot near the center of each image. For each image, I moved the dot a bit so that the arrangement of the four images on the Cinelerra timeline would show a circle of green dots when played back. First, I imported each still frame into a Cinelerra project formatted to 30fps and 320x180. Then, I stretched each png to the length of 30 frames using the "align cursor on frames" option and then re-added the first png image to the end of the timeline in order to complete the circle of dots. Finally, I added the interpolate effect with an "input frames per second" value of 1.

Update 5/17/2009Note that if you bring the video into Cinelerra and the thumbnail is green, this means that the first frame of the video is not a keyframe. This is a problem with VLC. You can avoid this problem by using this ffmpeg command in place of Step 4 above:ffmpeg -y -i OUTPUT.ps -acodec copy -f mpegts -qscale 1 OUTPUT.m2t*** end update ***

Update 11/17/06Last night, I found that doing performing other operations on your system like surfing the web or playing audio while running mplex or VLC convert may cause problems with the video as it uploads to the camera. So don't do anything while you convert your videos.

In my case, I was 28 minutes into an hour long video uploading to the cam when the import stopped. I no longer had uploading video displayed on the LCD screen of the cam. I only saw blue, the upload seemed to continue, but I got no final output. The solution was to remux the original streams using mplex and rebuild the MPEGTS using VLC. The important point being that one of these two processes is very sensitive to fluctuations in CPU or hard drive performance. So leave your PC alone while these processes are active.*** end update ***

Why Mule?

"Mules are not really stubborn. They can seem lazy because they will not put themselves in danger. A horse can be worked until it drops, but not so with a mule. The "stubborn" streak is just the mule's way of telling humans that things are not right. Mules are very intelligent and it is not a good idea to abuse a mule. They will do their best for their owner, with the utmost patience."About Mules